Suspension polymerization process

Abstract

A suspension polymerization process which comprises suspension polymerizing a mixture of monovinyl monomer and a polyvinyl monomer using carboxymethyl cellulose as a dispersing agent, the improvement wherein at least one metal compound of metal selected from the group consisting of iron, zinc and copper is present in the polymerization system in an amount of 0.5 to 10 wt %, calculated as the metal, based on the weight of the carboxymethyl cellulose.

What is claimed is: 
     
       1. A suspension polymerization process which comprises suspension polymerizing a mixture of a monovinyl monomer selected from the group consisting of methacrylic acid, acrylic acid or styrene as a major component and a polyvinyl monomer which comprises divinylbenzene as a major component using carboxymethyl cellulose as a dispersing agent, the improvement wherein at least one metal compound selected from the group consisting of a halide, inorganic acid salt, organic acid salt, hydroxide or oxide of iron, zinc and copper is present in the polymerization system in an amount of 0.5 to 10 wt%, calculated as the metal, based on the weight of the carboxymethyl cellulose. 
     
     
       2. The process of claim 1, wherein the ratio of the polyvinyl monomer to the monovinyl monomer is 1 to 120 mol%. 
     
     
       3. The process of claim 1, wherein the weight ratio of water to the monomers in the suspension mixture is 1/1 to 20/1. 
     
     
       4. The process of claim 1, wherein the amount of carboxymethyl cellulose used is 0.1 to 5 wt% based on the weight of water in the polymerization system. 
     
     
       5. The process of claim 1, wherein said metal compound is a chloride of at least one metal selected from the group consisting of iron, copper and zinc. 
     
     
       6. The process of claim 1, wherein said metal compound is an iron compound. 
     
     
       7. The process of claim 1, wherein said suspension polymerization is carried out at a temperature of 60 to 100° C. while stirring in a presence of 50 to 50,000 ppm, based on the total weight of the monomers, of a polymerization initiator. 
     
     
       8. The process of claim 1, wherein the amount of the metal compound is 0.8 to 8 wt%, calculated as the metal, based on the weight of carboxymethyl cellulose. 
     
     
       9. The process of claim 1 or 4, wherein the amount of carboxymethyl cellulose used is 0.5 to 2 wt% based on the weight of water in the polymerization system. 
     
     
       10. The process of claim 1 or 3, wherein the ratio of water to the monomers in the suspension mixture is 3 to 10 times by weight. 
     
     
       11. The process of claim 1, wherein said monovinyl monomer comprises methacrylic acid or acrylic acid as a major component and said polyvinyl monomer comprises divinylbenzene as a major component, and said suspension polymerization is carried out in a 15 to 25 wt% aqueous solution of sodium chloride, the amount of said aqueous solution being 1 to 20 times by weight based on the weight of the monomers. 
     
     
       12. The process of claim 1 wherein said monovinyl monomer is styrene. 
     
     
       13. The process of claim 12, wherein said metal compound is said iron compound. 
     
     
       14. The process of claim 13, wherein said iron compound is iron chloride.